Hi everyone,

So we welcomed yet another range rover to the house hold recently, and it does not have the locking rear E Diff, but I would like to fit it. I can see them for sale online at around £600 to £900, and I have heard of some of our friends over the pond asking the same question. From what I can see under the car at the rear, there seems to be a blanking plate on one of the sockets at the rear that most of the chassis loom plugs into.

I would like as much advice as possible on this if anyone is able to help with self study guides on the E diff, and also any retro fit advice, what is needed in terms of a loom etc. I have heard that theoretically you can actually wire it up independently, but I would much rather it was wired in as an oem replacement.

any advice greatly appreciated as usual.

I retro-fitted an e-diff to my MY12 4.4TDV8 L322.
Things to consider:
1. must use an e-diff with the same ratio which is unlikely to be the same as used with any other L405 engine.
2. best to acquire the control unit (RDCU) from the same vehicle so that the diff won't need to be calibrated
3. identify who/where to get the CCF altered
4. acquire the harness that connects to the e-diff and the harness that connects to the RDCU from the donor vehicle
5. If you have to make-up your own wiring, the control unit only requires permanent power (40A fuse), earth, ignition sense and HS canbus connections (tap into another module's wires eg park brake) and all the wires that run to the e-diff connectors.

The L322 uses multiple versions of the harness that includes the e-diff so I just purchased that section new. I was supplied with a RDCU from the same supplier but it was out of a D4 so the e-diff had to be calibrated. The mating connector for the harness from the e-diff did not have the wires from the RDCU but fortunately I already had terminals. The D4/L322 RDCU uses connectors which I acquired new as empty shells for which I purchased terminals from a connector supplier as LR only sold them as stupidly-priced repair kits. I don't know if the L405 uses the same physical RDCU as the D4/L322.

I have no information on the L405's wiring or connectors other than the 2012 version of Microcat only shows 1 chassis wiring harness for the rear (LR040386). However I am aware that the L405 information in this version of Microcat is incomplete.

Happy researching.

Great information Graeme thank you.

how do I go about finding out the ratio I have now, so I can match them up? its a 4.4 SDV8 2013 I have looked under the car at the diff and I can see no label or sticker with a part number, so I assume this must be hidden and is likely on top of the diff where the locking motor is. I am assuming its the 2.73 ratio diff

It looks like I will be able to access everything I need straight from a donor car, so I should be able to ensure the RDCU and loom all come from the same car. My main question is if I can obtain all of these parts and swap everything over, should there be some kind of plug and play harness already on the car, or would I need to splice into the can bus system in order for the car to recognize it on its cab bus network?

I am hoping that the L405 uses one harness throughout its range and then just plugs in extras that are specified at purchase rather than having 6 different looms, as appears to be the case with the L322. Interestingly our L322 2012 has a locking rear diff already and you can see it in action on the 4X4I menu and in the instrument cluster when it locks with the pad lock.

Thanks again

2012 Microcat shows only 2 e-diffs for the MY13 L405 - LR039512 for the 4.4 and LR039513 for the 5.0 SC so providing the donor is a 4.4 then the ratio will be correct. There are 4 different part numbers for the open diff so plenty of room for error there!

The L322's ediff harness plugs into a common socket but the corresponding wires to the RDCU were missing from the socket. The L322's RDCU harness is a version of the rear harness that runs across the back as well as running to the common socket so I had to provide the 40A cable to the fuse panel in the RH corner, including into the missing fuse-holder as well as providing the terminals and wires into the common connector.

I suggest that if you haven't already done it that you download from Topix the wiring schematic and connectors from the electrical reference library. I only have the L405's suspension section which I needed for my Llams kits but a day's subscription should be plenty of time.

The car will not recognise the RDCU until the CCF is modified to show that it is fitted. You need to be sure that someone has diagnostic equipment to make the change. I tested my electrics and CCF configuration prior to swapping the diffs with the ediff in a wheel-barrow at the back of the car to be sure that the car recognised the RDCU and the RDCU recognised the ediff. As it happened, I had fitted 1 wire to the wrong cavity in one of the connectors to the RDCU and as I didn't have the special tool to remove the terminal and couldn't otherwise release it (I've released terminals from lots of connectors but not this one!), I cut off the wire and fitted a new terminal.

It was a struggle for my son and me to pull the driveshafts out far enough to clear the diff seals having only removed the top hub bolts, with the handbrake cables also restricting movement. Maybe the L405 will be easier but the suspension can always be further dismantled if needed. You might want to get a garage to do the diff swap as they're not light.

Last edited by GraemeS on 28th Mar 2020 11:01am. Edited 1 time in total

theres a WM in the wiki that might help... ... - .- -.




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